#define _CRT_SECURE_NO_WARNINGS 1

#include<string>
#include<iostream>

using namespace std;

int main()
{
	string s;
	cin >> s;
	for (auto& e : s)
	{
		if ((e >= 'a' && e <= 'z') || (e >= 'A' && e <= 'Z'))
		{
			cout << e;
		}
	}

	return 0;
}